Embedded antenna design examples
- PCB antenna dualband – inverted F antenna
- Type: Inverted F antenna
- Multiband (e.g. GSM 900 / 1800 or GSM 850 / 1900)
- Easy to tune on center frequency
- Easy to tune on antenna impedance
- Size of antenna structure: 50mm x 10 mm
- Size of ground plane: 50 mm x 90 mm
- Size of whole PCB: 50 mm x 100 mm
This M2M device was designed by following all important rules of embedded antenna design. The developer got advice by an engineer with skills in antennas and long time experience in development of M2M devices. In this M2M design, the embedded PCB antenna was selected first. The ground plane length was selected by the lowest to frequency to transceive. If you have a closer look, then you will see that there are no holes for screws in the corners of the device. The screw that will be close to the radiator for GSM 850 / 950 will be made in plastic. This will help to minimise the parasitic load to the antenna. Between the GSM module and the embedded PCB antenna is a semiconductor that works as a 50 Ohm switch to an external antenna. The first quick performance test was done by the embedded channel scanner of the GSM module. The scanning of all GSM base station with external magnetic mount GSM antenna on big metal plate parallel to the embedded PCB antenna has shown, that the embedded GSM antenna catch more GSM base stations then magnetic mount antennas. The M2M device is in use in inside vending machines. Even inside the vending machines the signal strength is high enough to save the USD 4 for the external magnetic mount antenna, the drilling of holes at vending machines and the manual work for mounting antenna and coaxial cables. This saves further USD 8. All together the solution saves USD 12 per installation. The size of the first project is 4000 vending machines. This project customer will save USD 12 x 4000 = USD 48.000 with the first vending project.
Do not hesitate to drop an email to harald.naumann (at) gsm-modem.de to get advice on how to design a M2M device. On request you can get the contact details of this project customer as well.